Airplane step structure



I Aug. 25, 1942. L. EQREIsNER ETAL 2,294,000

5 AIRPLANE STEP STRUCTURE Filed Oct. '7, 1940 s Sheets-Sheet 1 JZUeRfoTrS, is M1515, fieasner O ZZ Gliiacker 1942- \L. E. REISNER ErAL AIRPLANE STEP STRUCTURE Filed Oct. 7, 1940 3 Sheets-Sheet 2 A -25,1942. I; E. REisN ER M. 2,294 000 AIRPLANE STEP STRUCTURE Filed Oct. 7, 1940 3 Sheets-Sheet 3 Patented Au 25, 1942 UNITED STATES ,PATENT OFFICE AIRPLANE STEP STRUCTURE Lewis I a. Reisner, Bellemeadt and Ora. G. Blocher, 'Donelson, Tenn., assignors, by mesne' and forth between assignments, to Vultee'Aircrai't, Inc'., a comration of Delaware Application oototer 7, 1940, Serial No. stones 6 Claims. (Olin- 117) Th present invention relates generallytoladder structures. More particularly the invention relates to that type of ladder structure which is associated with,- and forms a part of, the fuselage of an airplane and comprises a pair of similarly shaped ladders which are disposed at opposite sides of the fuselage and beneath the fuselage side doors and serve as a medium for permitting the persons using theairplane to ascend in concerned. is reduced to a minimum.-

Another object of the invention is to provide an airplane ladder structure of the type and character under consideration which comprises in addition to' the two ladders, simple and novel means for conjointly shifting thela'dders back their inoperative and operative positions.

A- further object of the invention is .to provide a ladder structure of the last mentioned char- 40* acter in which the ladder shifting means includes a control element in the interior of the airplane fuselage and is so designed and constructedthat the ladders when in their extended I y Y or operative position are locked against inward swinging movement except by manipulation or shift of the control element.

A still further object of 'the invention is to provide an airplane ladder structure which efficiently and effectively fulfills its intended purpose and not only may b constructed at a-comairplane ladder, structure will'be apparent'from.

a consideration of the following detailed description.

The invention consists in the several features which are hereinafter set forth and are more particularly defined by claims at the conclusion hereof.

In the drawings which accompany and form a part of this specification or disclosure and in nection with boarding of the airplane and also as 10 which like numerals of reference denote corre- ,a medium for permitting such persons to descend po in p r s r ut the v l V w ,7 the ground when leaving the airplane. Figure 1 is a fragmentary side view of an airone object of the invention is to provide an p e h v pp d thereto ladder Structure airplane ladder structure of this type which is m dy e v ti pa ts o t usela generally an improvement upon, and has certain of the airplane being broken away and other inherent advantages over, previously designed p ts being Shown in section for purposes of structures of'the same general character. st at o I f Another object of the invention is to provide Figure 2 is an enl rged vertical transverse seca ladder'structure of the type under consideration taken on the line 22 of Figure 1 and illus- 7, tion in. which the two ladders are mounted to zot a in t e d e s i t-h ir extended in pe a ive? swing back and forth between an inoperative Position; or out of the way position under the fuselage and igure '3 is a fragme y b tto Vi w of t an operative position wherein they are extended. airplane Showing fl ladders in their retracted I Another object of the invention is to provide inoperative P sit a an airplane ladder structure of the last men- Figure 4 i a large Scale Vertical transverse} tioned type and character. in which. the ladders S i n ill ra in n il e ti n nd when in their inoperative or out of the way posldesign of the means for conjoinfly if -tion, fit within ladder shaped pockets in the botswin in the ladd rs ack and f th tw tom portion of the airplane fuselage and thus their operat e a d inoperative pos ti s: aerodynamicdrag, as far as the airplane is con- I i re 5 is a fragment y hul'izontifl Section 5 drawings constitutes the preferred embodiment paratively low cost but also is light in weight as v well as durable.

Other objects of the invention and the various of the invention. It is disclosed in connection with, and forms a part of an airplane A and comprises a pair of ladders I. The airplane A is of standard or conventional design and embodies a fuselagea, a landing gear 41 an engine driven propellor a and a wing structure a. The fuselage a has the landing gear and wing structureailixed toit and carries the propellor 'a' and the engine for driving the propellor at the front end thereof. It has an empennage (not shown) at its rear end and embodies in the central portion thereof a combined pilot and pasenger compartment a. This compartment embodies a pilot seat a, in the front portion and a passenger seat a. in its rear portion. Two opposed similarly shaped doorways a! in the sides of the fuselage permit persons using the airplane to enter and leave the compartment a. These two doo w ys I advantages and characteristics of the present these are hinged at the front thereof so that they members and rungs of the may be swung outwards into an open position.

The. fuselage a of the airplane A embodies a fioorboard a for the compartment a and consists of a framework a and a skin a around the framework. The framework includes at the bottom thereof a pair of laterally spaced longerons a. and these are cross connected-by a cross member a The longerons The cross member a. is also of tubular design and is located directly in front of the passenger seat a. The bottom portion of the skin a of the fuselage a is transversely rounded or curved, as shown in Figure 4.

The ladders I of the ladder structure are cated ,on opposite sides of the fuselage a,.as shown in Figure 2, and are positioned directly fioorboard a 5 of the fuselage.

a. are of tubular design and are disposed beneath the rnerit I4 is disposed midway between the side portions of the'fuselage a and directlyin front of the passenger seat a. It is disposed within a two-piece housing l8 and extends transversely .Asshown in Figure 2, the gear segment IQ fits within-a transverse slot Is in the floorboard a and iscarried for rocking movement transversely of the fuselage by way of a bar type bracket 20.- The latter projects l0-upwardly from and is welded or otherwise se- 15 in the hub beneath thedoorways a". They are substantial-' 1y the same in size and shape and each consists of a front/side member 8,- a rear side member 9 and a painoi vertically spaced rungs Ill. The side ladders are of tubular design and hence are light in weight. The rungs of the two ladders extend. between, and are connected to, the'front and rear side members and serve to space the front sid members from the 9. lug 23 on that portion of the-hub of the upper gear segment that is diametricallyopposite the central teeth of the segment. I The two-piece housing I! consistsvof front and rear sections and these are so. shaped and positioned that they have rear side members and also to hold the front.

and rear members in laterally spaced and rigid relation. The ladders are disposed exteriorly 'of the fuselage. The upperrends of the front side an arcuate space 24 between them.- The lever ladder shifting means extends through this space 24 and is adapted to traverse the latter when it is swung in connection with rocking of the gear segment ll. Swinging of the 1ever 22 in one members arepivotally connected to the longerons a of the fuselage framework a by,

hinges H and the upper ends of the rear side members 9 of the ladders arepivotally connected to the longerons a" by hinges l2. The last mentioned hinges, i. e., the hinges l2,'- are connected to the longerons a a slight distancein front of the cross member a of the framework of the fuselage. The hinges II and I! are so positioned and'arranged that they permit the operative position wherein they extend downwardly and outwardly from the side portions of thefuselage and serve as a medium for per-. mitting persons using the airplane to ascend from the ground and enter the compartment via the doorways a" and also as a medium. for permitting the occupants of the airplane to descend to the ground in connection .with leaving the airplane, and an inoperative position wherein they extendiinwards along the' bottom portion of the fuselage a. The bottom portion of the skins of the fuselage. is provided .withua pair of'opposed pockets l3 for receiving the ladders 'I when the ladders are in their inoperative or retracted position. These pockets correspond in shape to direction results in counterclockwise rocking or rotation of the segment I4 and reverse swinging of the ,lever results in clockwise rocking or swinging of the segment II. The gear segment is adapted to be rotated through an arc of 180 only. By reason of'the fact that the lever-22 is directly in front of the passenger seat 11' it is readily accessible or manipulable" from within the compartment a. The lowergear segment A0 I! is disposed beneath, and is in mesh with, ladders I to swing back and forth between an a" of the 5: These braces are arranged in V'fashion and have the ladders and are of such depth that when the ladders are disposed therein the outer surfaces of the ladders are flush with the portions ets. By disposing the ladders I in the pockets when they are in their inoperative or retracted position aerodynamic drag is reduced to a minimum and the appearance of the airplane when of the fuselage skin that are adjacent the pock- 5o 'the latter is in flight is materially enhancedggg of the The hinges II and I! extend through holes in the skin (see Figure4) In addition to the ladders I the ladder structure comprises means .controllable from within the compartment affor. shifting or swinging the ladders I back and forth between their operative and inoperative positions. This means tially of simple designand comprises an upper gear segment II, a lower gear segment l5 and isessena pair of links [6 and I1.' The upper gear segthe upper gear segment ll. It is located in the space between the fioorboard a and the bottom portion of the fuselage skin a (seeFigures 2 and 4) It is rotatably mounted on a pivot pin which extends through, and projects forwardly from, the lower end of a vertically extending bar type bracket 26. The upper end of this bracket is welded or otherwise fixedly secured to the'central portion of the cross member fuselage framework. The pivot pin 25 underlies and extends in parallel relation with the pivot pin it for the upper. gear segment ll.

The bracket 26 is, reinforced against transverse bending by way of a pair of tubular braces 21.

their 1- ends welded to the central portion of the cross member a" and their lower ends welded to the sides of the bracket 26. The lower gear segment [5 is of half circle shape andhas a central hole through which the pivot pin 25 extends and carries a pair of radially extending arms 29 and 30; The arm 29 extends'oppositely to-the .arm 30 and projects away from the teeth segment 15. The link l6 of the shifting means extends between the outer end of the arm 29 and a bracket 3| on the upper portion of the rl'learc'lside member 9 of the starboard or right is pivotally connected to the outer end of the arm 29 by a pivot bracket 33. The clevis 32 is con nected to thelink l"by an externally threaded The latter is .2 2 constituting the control element of the a horizontally elon'gated hub 28. The latter has der: 1. The outer end ofthe link It is pivotally connected to the bracket 3! by'wayof a clevis'fl and the inner end of thelink lif tends through, and is movable in, a slot 36 which is formed in that portion of the starboard pocket I 3 that is designed to receive the rear side memher 9 of the starboard ladder. segment I5 is rotated throughout an arc of 180 in a clockwise direction, as viewed in Figure 2, the arm 29 and thelink l6 operate to swing the starboard ladder 1 inwards into its inoperative or retracted position in the starboard pocket I 3.

- When the lower gear segment is reversely rotated throughout an arc of 180 the arm 29 -and the link lli'operate to swing the starboard ladder 1 outwards into its operative or extended position. The upper and lower gear segments 14 and F5 are the same in size and are so arranged that 180 rocking of the upper segment by manipulation of the lever 22 effects 180 rotation or rocking of the lower segment IS. The arm 30 projects in the direction of, and past, the teeth of the lower gear segment l5 and is connected by the link I! to a bracket 31on the upper portion of the rear side member 9 of the port .or left hand ladder l The link I! extends substantially horizontally and embodies a clevis 3 erative position are locked against inward movement except by clockwise rotation of the lower gear segment l5 and this'canonly be accomplished by rocking ofgthe upper gear segment I 4 When the gear through the medium ofthe lever 22. In other words the various parts of the shifting means are so arranged that the ladders I are selflooking or irreversible when in their operative or extended position and can only be retracted by swinging the lever 22 in the properdirection. The stop lug 44 is adapted when the ladders are. swung inwards into their inoperative or retracted position to engage the central portion of the bar type bracket 26, as shown in Figure 4, and thus prevent any further inward movement of the ladders. When the ladders 1 are in their operative position the links l6 and H, the arms 29 and 30. the two gear segments and thecontrol lever 22 are positioned as shown in Figure 2. In such' position of the aforementioned parts the lad.-

38 at its outer end-whereby it is pivotally connected to the bracket 3'I.- The inner end of the link I! is connected to the outer or distal end of the arm by av pivot bracket 39. The clevis 38 is connected to the-outer end of the link I! by an externally threaded stem 40 and a lock nut 4| in order that it may be adjusted to or from the link should it be necessary to lengthen or shorten the link as'a whole. The central portion of the link I! .extends through and moves within a transverse slot 42 in that portion of the port pocket l3 which receives the rear side member 9 of the port ladder I. The arm 30 and the link I! are so arranged that when the lower gear segment I5 is rocked or'turned in connection with shift of the starboard ladder I into its operative position they operate to shift the port ladder into its operative or extended position. The two links it and I1 together with their arms 29 and 30 conjointly shift the ladders outretracted position ders are locked in place and hence they may he stepped on by persons entering or leaving the compartment a in the fuselage. When it is desired to retract the ladders 1 it is only necessary to swing the lever 22 upwards and over throughout an arc of 180. Such movement on the part 'of the lever causes the upper gear segment l4 to swing 180 in a counterclockwise direction, as viewed in Figure 2, and the lower gear segment IE to swing or rotate 180 in a clockwise direction. Such rotation or swinging on the part of the lower. gear segment operates through the medium of the arms 29v and 30 and the links l6 and I I to swing theladders 1 inwards and upwards into their inoperative or in'the pockets l3. From the foregoing description it is manifest that a 180 swing of the' lever 22 in. one direction operates to swing the ladders 1 into their operative position and a reverse 180 swing,of the lever results in the ladders swinging into theirinoperawards into their operative position when the lower gear segment I5 is tumed' counter'clockextending stop lug 44 on the other corner of such segment serve to limit the lower segment 5 to rotation throughout an arc of 180 only. The stop lug 43 is so arranged that when the lower gear segment I5 is rocked in'a counterclockwise direction, as viewed in Figure 3, in order to swing the ladders into their operative position it abuts against the centralportion of the bar type bracket 26 and prevents further clockwise rotation of the lower gear segment. When the ladders I are in their operativeposition, as shown in Figure 2, the bracket 33 is above an imaginary straight line running between the pivot pin 25 and the clevis 32 and the bracket 39is below an imaginary line between the pivot pin 25 and the clevis 38 with the result that any weight on the ladders tends to rotate the segment gear IS in a counterclockwise direction, as viewed in Figure 2, and this is precluded by the stop lug 43. Because of. the arrangement of the links l6 and I1 and the arms 29 and 30 and the location of the stop lug 43 the ladders I when in their optive position within the ladder-shaped pockets in the bottom portion ofthe fuselage skin a". In the event that the ladders I do. not properly fit within their pockets when the lower gear segment I5, as viewed in Figure 4, is rotated clock-y wise to its fullest extent proper adjustment may be made by adjusting the clevises 32 and 38 with respect to their respective links.

The herein described ladder structure is simple indesign and efiectively and efflciently fulfills its intended purpose. It is light in weight while at the same time it is sufficiently durable and has the requisite strength for its intended purpose. .The structure is readily controllable from within the fuselage interior, i. e., the compartment a and cannot be collapsed or retracted when in its operativeposition by the placement of excessive weight or pressure on the ladders. Due to the fact that the ladders are disposed wholly within the ladder-shaped pockets I3 in.

the bottom portion of the skin of the fuselage the ladders do not cause any appreciable aerodynamic drag during flight or travel of the airplane A.

Whereas the ladder structure has been described as comprising two ladders it is to be understood that a single ladder on an airplane having a fuselage with a single door is within the purview of the invention. It is also to be understood that the invention is not to be "restricted to the details set forth since these may be modifled within the scope of the appended claims without departing from the spirit and scope of the invention.

Having thus described the invention what we claim as new and desire to secure by Letters Patent is:

1. In a vehicle body having adoor closed access doorway and a pocket adiacentthe doorway, a. ladder structure comprising a ladder pivotally connected to the body and arranged so as to swing back and forth between an operative position wherein it is disposed externally of, and in close proximityto, the doorway and an inoperative position wherein it is pocket, and mechanism for shifting the ladder back and forth between its operative and inoperative positions including an element arranged in the body to rock or swing back and forth throughout an arc of ,less than 360 degrees and a link having its ends pivotally connected to the element and ladder, respectively, said mechanism being designed so thatwhen the ladder is in its operative position it is irreversible or selflocking except by rocking of the element in one direction.

2. In an airplane fuselage having a doorway in one side thereof and an external laddershaped pocket in its bottom directly beneath the doorway, a ladder structure comprising a ladder of the same shape as the pocket hingedito the fuselage at a point directly beneath the doorway and arranged so as to swing back and forth between an operative position wherein it extends downwardly and outwardly from the doorway bottom and an inoperative position wherein it is disposed substantially wholly within the pocket, and manually manipulable mechanism for swinging the ladder back and forth between its operative and inoperative positions, consisting of a hand lever in the fuselage interior together with lever actuated gearing and a link between the gearing and the ladder/said mechanism being arranged and designed so that when the ladder is in its operative position it is irreversible or locked against movement except by actuation of the gearing through the medium of the lever.

3. In a vehicle body having doorways in the sides thereof, a ladder structure comprising a pair of ladders associated with the doorways respectively and connected to the body so that they are shiftable back and forthbetween an operative and an inoperative position with respect to the doorways, and means including an actuating element in the body for conjointly shift- 7 disposed in said,

ing the ladders back and forth between their operative and inoperative positions.

" 4. In a vehicle body having door closed doorways in its sides and external-pockets adjacent the doorways, a ladder structure comprising a pair of ladders associated with-the doorways re,- spectively and hinged to the body so as to swing back and forth between an operative position wherein they extend downwardly and outwardly 10 from the doorway bottoms and an inoperative position wherein they are disposed in the pockets, and means including an actuating lever in the body together with lever driven gearing for conjointly swinging the ladders back and forth between their operative and inoperative positions.

5. In an airplane fuselage having doorways in the sides thereof and extemalladder-shaped pockets in its bottom portion directly beneath the doorways, a ladder structure comprising a pair of ladders shaped conformably to the pockets and hinged to the fuselage at points directly beneath the doorways so that they may be swung back and forth between an operative position wherein they extend downwardly and outwardly from the bottom portions of the doorways and an inoperative position wherein they are disposed substantially wholly within the pockets, and means including a ,control element in the fuselage interior for conjointly swinging the ladders back and forth between their operative and inoperative positions.

' 6. In an airplane fuselage having doorways in the sides thereof and external ladder-shaped pockets in its bottom portion directly beneath the doorways, a ladder structure comprising a pair of ladders shaped conformably to the pockets and hinged to the fuselage at points directly beneath the'doorways and so that they maybe swung back and forth between an operative po- 40 sition wherein they extend downwardly and out-- wardly from the bottom portions of the doorways and an inoperative position wherein they are disposed substantially wholly within the pockets, and means for conjointly swinging the ladders back and forth between their operative and inoperative positions, including an actuating lever in the fuselage interior together with lever driven gearing, and arranged and designed so that when the ladders are in their operative position they 59 are irreversible or looked against movement except by movement of the lever; v

LEWIS E. REISNER. QRA G. BLOCHER. 

